This invention relates generally to a method and apparatus for immobilizing toxic or hazardous liquids to enhance the safety of interim storage and transportation.
More specifically, this invention relates to the addition of activated polymer particles to a toxic liquid held within a container to immobilize and solidify the liquid therein.
The safe handling, storage, transportation and disposal of toxic liquid wastes, especially those comprising halogenated aromatic hydrocarbons, has been of increasing public and governmental concern. Examples of particularly troublesome materials include dioxin-contaminated herbicides and manufacturing waste solvents and polychlorinated biphenyls (PCBs). Dioxin is a very potent carcinogen while PCBs are an acute toxin and are known to affect and interfere with reproduction success in animals. Halogens aromatic hydrocarbons in general, and PCBs in particular, are extremely stable compounds, highly resistant to degradation in the natural environment and essentially inert toward other chemicals including common oxidizing agents, acids and bases. PCBs are soluble in most of the common organic solvents but only very slightly soluble in water. Because of their stability and general chemical inertness, these compounds have found wide use as dielectric fluids, heat transfer liquids, hydraulic fluids and plasticizers.
Although new industrial uses of PCBs have been curtailed there is a large volume of PCBs in storage in the United States and many devices, especially transformers and capacitors, still in use contain PCBs, all of which will eventually require safe disposal. High temperature incineration is now considered to be the only appropriate disposal technique for PCB liquids and adequate approved incinerator capacity for such disposal is presently unavailable. Consequently, there exists a pressing problem of interim storage of PCBs in a safe manner and the need for transportation methods to remove PCBs and similar hazardous liquids from their source to a disposal facility. Typical interim storage methods in use at this time include containment in drums or barrels. Corrosive failure of such containment vessels is a relatively common experience and rupture of the vessels during transportation is an ever-present hazard.
There is disclosed in the inventor's prior U.S. patent application Ser. No. 117,235 a method for the extremely rapid dissolution of polymeric materials in compatible liquid solvents. The technique therein disclosed comprises the cryogenic comminution of polymeric materials to form activated particles which dissolve with great rapidity in solvent liquids. The disclosure in that application is incorporated herein by reference.
A paper entitled "Several Remedies for the Treatment of Spillages of Liquid Hazardous Chemicals" by G. K. Braley, published in the Proceedings of the 1980 Conference on Control of Hazardous Material Spills, May 13-15, 1980, Louisville, Ky., pages 103-108, describes a method for containing spillages of various chlorinated residues and halogenated solvents. As reported in this paper, treatment of such materials with Hycar 1422 (a polyacylonitrile-butadiene copolymer manufactured by B. F. Goodrich) resulted in the solidification of the spilled liquids.
A report prepared by the CALSPAN Corporation for the National Environmental Research Center, entitled "Methods to Treat, Control and Monitor Spilled Hazardous Materials," dated June, 1975, pages 62-70, describes a method for immobilizing hazardous chemical spills. Treatment of the spills with a gelling agent consisting of four active ingredients and one inert powder congealed chlorinated liquids into a viscous, sticky mass.